Find the row whose product has maximum count of prime factors | C # implementation to find the row whose product has maximum number of prime factors ; function for SieveOfEratosthenes ; Create a bool array " isPrime [ 0 . . N ] " and initialize all entries it as true . A value in isPrime [ i ] will finally be false if i is not a prime , else true . ; check if isPrime [ p ] is not changed ; Update all multiples of p ; Print all isPrime numbers ; function to display the answer ; function to Count the row number of divisors in particular row multiplication ; Find count of occurrences of each prime factor ; Compute count of all divisors ; Update row number if factors of this row is max ; Clearing map to store prime factors for next row ; Driver code
using System ; using System . Collections . Generic ; class GFG { static readonly int N = 3 ; static readonly int M = 5 ; static int Large = ( int ) 1e6 ; static List < int > prime = new List < int > ( ) ; static void SieveOfEratosthenes ( ) { bool [ ] isPrime = new bool [ Large + 1 ] ; for ( int p = 0 ; p <= Large ; p ++ ) isPrime [ p ] = true ; for ( int p = 2 ; p * p <= Large ; p ++ ) { if ( isPrime [ p ] == true ) { for ( int i = p * 2 ; i <= Large ; i += p ) isPrime [ i ] = false ; } } for ( int p = 2 ; p <= Large ; p ++ ) if ( isPrime [ p ] ) prime . Add ( p ) ; } static void Display ( int [ , ] arr , int row ) { for ( int i = 0 ; i < M ; i ++ ) Console . Write ( arr [ row , i ] + " ▁ " ) ; } static void countDivisorsMult ( int [ , ] arr ) { Dictionary < int , int > mp = new Dictionary < int , int > ( ) ; int row_no = 0 ; long max_factor = 0 ; for ( int i = 0 ; i < N ; i ++ ) { for ( int j = 0 ; j < M ; j ++ ) { int no = arr [ i , j ] ; for ( int k = 0 ; k < prime . Count ; k ++ ) { while ( no > 1 && no % prime [ k ] == 0 ) { no /= prime [ k ] ; if ( mp . ContainsKey ( prime [ k ] ) ) mp [ prime [ k ] ] = prime [ k ] + 1 ; else mp . Add ( prime [ k ] , 1 ) ; } if ( no == 1 ) break ; } } int res = 1 ; foreach ( KeyValuePair < int , int > it in mp ) { res *= ( it . Value + 1 ) ; } if ( max_factor < res ) { row_no = i ; max_factor = res ; } mp . Clear ( ) ; } Display ( arr , row_no ) ; } public static void Main ( String [ ] args ) { int [ , ] arr = { { 1 , 2 , 3 , 10 , 23 } , { 4 , 5 , 6 , 7 , 8 } , { 7 , 8 , 9 , 15 , 45 } } ; SieveOfEratosthenes ( ) ; countDivisorsMult ( arr ) ; } }